The other recommended additive is sun block. This may sound unusual but sun block has been used for outdoor foam tire racing for as long as I can remember. Of course, there are a lot of brands of sun block out there so I would suggest starting with Coppertone SPF 30. Sun block tends to be used mostly on low to medium grip conditions and is applied after the primary additive such as Paragon has been applied. When using additive, the amount of time it is left on the tire determines the level of effect. Apply additive to the full surface of the rear tire for maximum rear grip but only the inside 1/4 of the front tires. The amount of additive applied to the front can be increased or decreased depending on the amount of steering desired. Also, experiment with the duration you let the additive sit before wiping it off and running. The longer the additive is left on the tire, the softer the tire will become and the depth of absorption will also increase.